Hello All,
i have recently bought a Kayak that needs some SERIOUS REPAIRS. I am asking for any kind of advice on how to fix these. I have been looking up Plastic Welding, but i want to know if there is a better way. Any advice is greatly appreciated.

Warm Regards,

-Nate G.

*8/20/18 UPDATE
Thank you All for your advice. I have gone along to Try and PLASTIC WELD this Bali 13.5 Kayak. See pics below. I had to heat and reform the back of the bottom kayak. It was warped open. Used a strap to hold in place, heat, and plastic weld with Red HDPE (#2) i harvested from an old tool box. Melted some wire mesh in place and added more plastic over that. Once this is all done, i plan on sanding the plastic down and covering the entire bottom of the kayak with some king of Bed-liner/Plastic/Rubber in a Can, just for added strength and durability.

All comments and advice is GREATLY Appreciated.

It should RIP

Plastic welding those tears might be pretty tricky. You would have to get the edges closely approximated for it to work and it is not a job I would attempt on your own. I think it would take an experienced plastic welder for it to have any chance of success.

Also, plastic welding only works on linear polyethylene. It will not work on cross-link polyethylene. I see from the MIC portion of the HIN that this is a Sundolphin kayak. It is almost certainly linear polyethylene, but if you plan to have someone try welding it, I would call Sundolphin first and confirm that it is made from a linear polyethylene.

It is obvious that someone tried stitching the rend together and bonding some type of tape or fabric over it which failed. It is hard to get anything to bond to polyethylene. West Systems G Flex epoxy is your best bet, but you must first prep the surface by cleaning it thoroughly, then flame oxidizing it with a hand-held propane torch just prior to applying the epoxy. If you are serious about trying to repair this, you could try approximating the tear shown in the lower photo using wire through the holes already drilled, then filling in the crack with thickened G Flex, and finally covering the whole thing with a fiberglass patch.

But seriously, this type of kayak typically sells for less than $200 new. The materials required to do a repair with epoxy and cloth could easily come to almost half that if you count incidental expenses like solvents, disposable gloves, sand paper, masking tape, mixing containers, application tools, and if you have to buy a propane cylinder and torch burner head.

I would probably be inclined to pull the tears together as best possible with strong wire, and cover them outside (and in, if you can get to them) with Gorilla Tape.

@rnsparky said:
It should RIP

Agree… it’s a 2016 Sun Dolphin

Rotomolded plastic (how this kayak is made - rotomolding polyethylene plastic) has the benefit of being nearly indestructible, which makes it great for entry level kayaks. The downside that goes with that is that when you do find a way to destruct it, they are nearly impossible to repair.

The repair process, if it could be done, is to plastic weld it.

What you have going for you:

  • As kayaks get older, and the plastic ages, it gets even less likely a repair would work. Yours probably has not had this issue yet.
  • Not totally sure, but it looks kike the damage would be above the water line? If so, this reduces the need for a perfect repair and reduces the risk should the repair let go (boat should float if it does to get you back to safety).

What you don’t have going for you:

  • Plastic welding does not bring it back to the same strength of the original molded plastic. With a split that large, the chance of it re-opening after repair is pretty high. Along with welding the two sides together, you may want to bolt a some material behind this to either side to provide strength (something that functions like a butterfly bandage works on a slice cut)
  • Plastic welding is hard. That is going to be a rather involved process to fix a cut that large.
  • A decent plastic welder will cost almost as much as a new version of that kayak.

I wouldn’t even consider repairing that, but then again, I am not all that handy a person.

I’m a proponent of repair whenever feasible, but I’d cut your losses on this one. Spend many hours and a few hundred dollars on the repair and it’s just as likely to open up a huge crack right next to your repair.

That is a split not a crack.
It’s a Sundolphin?..There’s an infomertial where the guy saws a boat in half then tapes it back together and takes it for a ride. Costs about $15 for a roll. Works great.

Club members have used duct tape to patch holes in $$$$ boats . Duct tape let’s go in water.

Call Waste Management it’s over sorry. If you paid a dime it was 10 cents to much. Better use would be a planter.

Hold the propane torch very close while oxidizing the repair area. When it begins to melt, keep the flame on it and it should burst into flames. Stand back and enjoy the bonfire.

@magooch said:
Hold the propane torch very close while oxidizing the repair area. When it begins to melt, keep the flame on it and it should burst into flames. Stand back and enjoy the bonfire.

Good one… but there should really be a recycling program for the hoards of cheap KSO’s that won’t last more than a few years.

No sense making the problem worse by burning them. :slight_smile:

@magooch said:
Hold the propane torch very close while oxidizing the repair area. When it begins to melt, keep the flame on it and it should burst into flames. Stand back and enjoy the bonfire.

Serious air pollution.

There have been a couple of manufacturers who would accept cut up polyethylene kayaks to recycle the plastic. I believe that Dagger and Liquid Logic did for a while.

The problem is that the boats made from recycled poly are weaker and the recycled PE powder was considerably more expensive than virgin PE powder. So the whole process was entirely cost-inefficient.

Just for the heck of it get the wide gorilla tape and fix it. I think you’ll get a few uses out of it! Make a good commercial

If you are serious about trying to repair this boat, here is something I happened across that might be of interest:


Refer to the very last section which details how to attach a plastic patch over a hole or tear using pop rivets. You could conceivably use either ABS or sheet polyethylene as a patch. If a PE patch was used, you could seal the edges by melting in some PE welding rod using a torch. You could also seal the edges using a fillet of G Flex epoxy thickened with silica powder.

You would need to seal the pop rivets with Lexel to keep water from leaking in.

Flexseal should do it. https://www.flexsealproducts.com/

Seriously, we carry the Flexseal tape for emergency repairs. It’s ugly but works.

hat are you planning to do with this boat? I see North Carolina in your profile, which means you may be near whitewater. If that is the case you probably should not try, because none of the patch solutions above are likely to hold up in those conditions… .

Not the same type of work you are doing (more filling holes, not fixing cracks), but here is a video I just saw from a guy trying to fix a modified kayak he bought cheap from a garage sale. Might be useful if you go for the fix.

Good activity for someone who has way too much time on their hands.